The STEREO (Solar TErrestrial RElations Observatory) mission used a pair of spacecraft launched into orbit around the Sun. One slowly moved ahead of the Earth, and the other slowly lagged behind. Their separation allowed for simultaneous stereoscopic images to be taken of the Sun. The lagging spacecraft failed in 2014, but the leading spacecraft is still operational. This picture of the Sun was taken with the Extreme Ultraviolet Imager onboard the Solar TErrestrial RElations Observatory Ahead (STEREO-A) spacecraft. The spacecraft collects images in several wavelengths of light that are invisible to the human eye. This image shows the sun at a wavelength of 17.1 nm which which is usually coded in blue for false color imaging. STEREO-A is out of communication with the Earth when it’s on the far side of the Sun, where it operates in safe mode, collecting and saving data from its instruments. This image was taken by STEREO-A in July, 2015, from a point of view on the far side of the solar system as it had moved far enough around in its orbit to regain contact with the Earth.
Image Credit: NASA